Strapping tool

Abstract: A strapping tool (10) of a type used to apply a steel strap (12) in a tensioned loop around a package (14) and to join the strap via a series of interlocking joints (16) comprising interlockable shoulders punched into overlapped ends of the strap (12) includes a base (60) extending longitudinally and defining a pair of recesses (70, 72). A frame (78) upstanding from the base (68) is mounted integrally to the base (68). In a mechanism for admitting the overlapped ends of the strap into the tool, for retaining the overlapped ends, and for releasing the overlapped ends from the tool, a pair of latches (100, 106) having hooked ends (102, 108) are mounted pivotably to the base (68) so as to be pivotable between closed positions wherein the latches (100, 106) are positioned with the hooked ends (102, 108) extending into the recesses (70, 72) to retain the overlapped ends between the latch (100, 106) and the base (68) and between the hooked ends (102, 108) and the frame (78) and an open positions wherein the latches are displaced angularly from their closed position to admit the overlapped ends into the tool (10) and to release the overlapped ends from the tool (10). The latches (100, 106) are biased into their closed position. Co-acting elements including a lever (70), which can be manually squeezed toward an actuating handle (40) of the strapping tool (10), and a camming member (120), which is arranged to cam the latches (100, 106), are provided for pivoting the latches (100, 106) from their closed position into their open position.

Description: This invention pertains to a strapping tool of a type used to apply a steel-strap in a tensioned loop around a package and to join the strap via a series of interlocking joints comprising interlockable shoulders punched into overlapped ends of the strap. In a strapping tool of the type noted above, an actuating handle is provided, which is arranged to be manually oscillated. The handle rotates an output shaft, which actuates a series of cams, via an input shaft, to which the handle is coupled, and intermediate gears. The cams drive a series of punches, which punch interlockable shoulders into overlapped ends of the strap. Tremper et al. U.S. Patent No. 4,825,512 provides a recent example of such a strap having such a series of interlocking joints. As disclosed in Nix U.S. Patent No. 5,136,888, a strapping tool of the type noted above may incorporate a mechanism for converting oscillatory rotation of the input shaft to uni-directional rotation of the output shaft. EP-0,091,578 discloses a strapping tool in accordance with the preamble of claim 1 which includes a hooked-shaped rocking lever for admitting overlapped ends of the strap into the tool, for retaining the overlapped ends, and for releasing the overlapped ends from the tool. This invention improves a strapping tool of the type noted above. The strapping tool is used to apply a steel strap in a tensioned loop around a package and to join the strap via a series of interlocking joints comprising interlockable shoulders punched into overlapped ends of the strap. The strapping tool comprises a fixed structure, which includes a base extending longitudinally and a frame upstanding from the base, and a mechanism for admitting the over-lapped ends of the strap into the tool, for retaining the overlapped ends, and for releasing the overlapped ends from the tool, the mechanism including a latch having a hooked end, the latch being mounted pivotably so as to be selectively pivotable between a closed position wherein the latch retains the overlapped ends and an open position wherein the latch is angularly displaced from the closed position to admit the overlapped ends into the tool and to release the overlapped ends from the tool, the latch being biased into the closed position, the mechanism further including a lever for moving the latch from the closed position into the open position, and is characterised in that the latch is mounted pivotably to the base, in that the mechanism further comprises an elongate camming member mounted movably to the frame so as to be longitudinally movable between an advanced position corresponding to the closed position of the latch and a retracted position corresponding to the open position of the latch, the camming member having a cam slot co-acting with a camming end of the latch so as to pivot the latch from the closed position into the open position upon longitudinal movement of the camming member from the advanced position into the retracted position and so as to pivot the latch from the open position into the closed position upon longitudinal movement of the camming member from the retracted position into the advanced position, in that in the closed position the latch retains the overlapped ends between the latch and the base and between the hooked end of the latch and the frame, and in that the lever is linked to the camming member in such manner that pivoting of the lever from the latching position into the unlatching position results in longitudinal movement of the camming member from the advanced position into the retracted position, the camming member being biased into the advanced position so as to bias the lever into the latching position. Ordinarily, a strapping tool of the type noted above comprises a handle mounted pivotally to the frame so as to be pivotable over a range of pivotal movement, between a forward limit of the range and a reverse limit of the range. The handle may be advantageously positioned near the lever, when the actuating handle is positioned at the reverse limit of the range, so as to permit a user employing one hand then to pivot the lever from the latching position into the unlatching position by grasping the actuating handle and the lever and by squeezing the lever toward the handle. Preferably, the axis about which the lever is pivotable is a transverse axis, and the mechanism further comprises a transverse member spaced from the transverse axis and movable about the transverse axis as the lever is pivoted about the transverse axis. Preferably, moreover, the camming member has an end portion defining an aperture, through which the transverse member extends, the end portion co-acting with the transverse member in such manner that the transverse member moves the camming member from the advanced position into the retracted position upon pivoting of the lever from the latching position into the unlatching position. A preferred embodiment of this invention will now be described with reference to the accompanying drawings, in which:- Figures 1 and 2 are fragmentary, perspective views of a strapping tool embodying this invention, as used to apply a steel strap around a package. In Figure 1, portions of two side covers are broken away so as to reveal internal details. Figure 3 is a similar view on a larger scale. In Figure 3, some elements including one of the side covers and an actuating handle are removed so as to reveal internal details. In Figure 3, the strap and package are not shown. Figure 4 is a fragmentary, perspective, exploded view of some elements of a mechanism of the strapping tool for admitting, retaining, and releasing the overlapped ends of a steel strap, which is not shown. Figure 5 is a fragmentary, perspective, assembled view of some elements of the mechanism for admitting, retaining, and releasing the overlapped ends of a steel strap, which is shown after a series of interlocking joints have been formed in its overlapped ends. Figure 6 is an enlarged, fragmentary detail taken from Figure 5. As shown in the drawings, particularly in Figures 1, 2, and 3, a strapping tool 10 of the type noted above constitutes a preferred embodiment of this invention. The strapping tool 10 is used to apply a steel strap 12 in a tensioned loop around a package 14 and to join the strap 12 via a series of interlocking joints 16 (see Figure 5) comprising interlockable shoulders 18 punched into the overlapped ends of the strap 12. As shown in Figures 4 and 5, the strapping tool 10 embodies a mechanism 20 for admitting the overlapped ends into the tool 10, retaining the overlapped ends so as to facilitate punching the series of interlockable shoulders 18 into the overlapped ends, and releasing the overlapped ends from the tool 10. While the overlapped ends of the strap 12 are retained by the mechanism 20, the series of interlockable shoulders 18 may be then punched into the overlapped ends via a series of cams 22, which are arranged to drive a series of punches 24. The cams 22 and punches 24 may be substantially similar to the cams and punches used in known strapping tools of the type noted above. The cams 24 are driven by a mechanism 30 (see Figure 3) for converting oscillatory rotation of an input shaft 32 (Figure 3) to uni-directional rotation of an output shaft 34 mounting the cams 24 so as to enable the cams 24 to rotate conjointly with the output shaft 34. The mechanism 30 may be substantially similar to the converting mechanism disclosed in a co-pending European patent application filed concurrently with Attorney's reference 80/4913/02 and published as EP-A-647 800. Alternatively, the mechanism 30 may be substantially similar to the converting mechanism disclosed in Nix U.S. Patent No. 5,136,888, the disclosure of which patent is incorporated herein by reference. An actuating handle 40 is secured to the input shaft 32 so that the input shaft 32 is rotated about its axis as the actuating handle 40 is pivoted about the same axis. The actuating handle 40 is pivotable manually over a range of pivotal motion, between a forward limit and a reverse limit, as limited by the mechanism 30. In Figure 2, the actuating handle 40 is shown at its forward limit in dashed lines and at its reverse limit in full lines. The strapping tool 10 comprises a mechanism 50 for tensioning the overlapped ends of the strap 12. Except as shown in the drawings and described herein, the mechanism 50 may be substantially similar to tensioning mechanisms used in known strapping tools of the type noted above. The mechanism 50 comprises a transverse shaft 52, to which a tensioning handle 54 is secured so that the transverse shaft 52 is rotated about its axis as the tensioning handle 54 is pivoted about the same axis, along with a knurled wheel 56 and a ratchet gear 58. The knurled wheel 56 and the ratchet gear 58 are coupled to each other so as to be conjointly rotatable and are mounted on the transverse shaft 52 via a clutch (not shown) interposed between the ratchet gear 58 and the transverse shaft 52 and a pawl (not shown) co-acting with the ratchet gear 58 so as to permit the knurled wheel 56 and the ratchet gear to rotate with the shaft 52 only in one rotational direction (counter-clockwise in the drawings) when the tensioning handle 54 is pivoted in the same directional and so as to prevent the knurled wheel 56 and the ratchet gear 58 from rotating when the tensioning handle 54 is pivoted oppositely. The shaft 52 is journalled to two pivotal links, in a manner to be later described, namely a link 60 and a link 62. The pawl noted above is mounted operatively to the link 62. The strapping tool 10 comprises a fixed structure, which includes a base 68 extending longitudinally, defining a pair of similar, longitudinally spaced recesses, namely a forward recess 70 and a rearward recess 72. The base 68 mounts a knurled pad 74. The fixed structure further includes a frame 76, which is assembled from multiple parts, which is mounted fixedly to the base 68 via fasteners (not shown), and which is upstanding from the base 68, and two side covers 78, which are secured by fasteners (not shown) to the frame 76. The output shaft 34 is journalled to the frame 76. A lever 80 is mounted to the link 60, via a fastener 82, and to the link 62, via two fasteners 84, at a flanged end 86 of the lever 80. The links 60, 62, are mounted pivotably to the frame 76 via a pivot pin 88 so as to be pivotably movable with the lever 80, over a range of pivotal motion, between a normal position of the links 60, 62, and the lever 80 and a displaced position there-of. The pivot pin 88 defines a transverse axis. The links 60, 62, and the lever 80 are shown in the normal position in Figures 2 and 3 and in the displaced position in Figure 1. The links 60, 62, and the lever 80 are biased to the normal position in a manner to be later described. When the links 60, 62, and the lever 80 are positioned in the normal position, the overlapped ends of the strap 12 are pinched between the knurled wheel 56 and the knurled pad 74. Thus, the knurled wheel 56 bears against an upper one of the overlapped ends, while a lower one of the overlapped ends bears against the knurled pad 74. As the tensioning handle 54 is oscillated, the knurled wheel 56 draws the strap end bearing against the knurled surface of such wheel 56 and the other end of the strap 12 bears against the knurled pad 74, which prevents such other end from slipping, whereby the strap 12 is tensioned. Further structural and functional details of the mechanism 50 for tensioning the strap 12 are outside the scope of this invention. Except as disclosed herein, the tensioning mechanism 50 may be substantially similar to the tensioning mechanisms used in known strapping tools of the type noted above. As shown in Figures 4, 5, and 6, the mechanism 20 for admitting the overlapped ends into the tool 10, retaining the overlapped ends so as to facilitate punching the series of interlockable shoulders 18 into the overlapped ends, and releasing the overlapped ends from the tool 10 comprises a pair of similar, longitudi-nally spaced latches, namely a forward latch 100 having a hooked end 102 and a camming end 104 and a rearward latch 106 having a hooked end 108 and a camming end 110. Each latch is mounted pivotally to the base 68, via a pivot bracket 112, which is secured to the base 68 by a fastener 114, and via a pivot pin 116, which extends through an aperture in the pivot bracket 112 and through an aperture in such latch, so as to be pivotably movable about a longitudinal axis defined by the pivot pin 116. The mechanism 20 further comprises a camming member 120, which is an elongate, blade-like member mounted movably to the frame 76 so as to be longitudinally movable between an advanced position and a retracted position. The advanced position corresponds to the latching position of the lever 80 and to the closed position of the latches 100, 106, and the retracted position corresponds to the unlatching position of the lever 80 and to the opened position of the latches 100, 106. The camming member 120 has two camming slots, namely a forward slot 122 receiving the camming end 104 of the forward latch 100 and a rearward slot 124 receiving the camming end 110 of the rearward latch 106. Each of the camming slots 122, 124 has a horizontal portion extending toward the transverse shaft 52 and an inclined portion extending oppositely. As shown, the forward slot 122 is closed at both ends, whereas the rearward slot 124 is opened at one end. The camming slots 122, 124, co-act with the camming ends 104, 110, of the latches 100, 106, so as to pivot the latches 100, 106, from the closed position into the opened position upon longitudinal movement of the camming member 120 from the advanced position into the retracted position. As described above, the transverse shaft 52 is spaced from the transverse axis defined by the pivot pin 88 mounting the links 60, 62. The camming member 120 has, near its rearward end 126, an end portion 130 defining a generally U-shaped pocket 132, which opens upwardly and through which the shaft 52 extends. The shaft 52 has a circular cross-section, which permits relative rotation of the shaft 52 and the pocket 132, where the shaft 52 extends through the pocket 132. The end portion 130 of the camming member 120 co-acts with the shaft 52 in such manner that the shaft 52 moves the camming member 120 longitudinally from the advanced position into the retracted position upon pivoting of the lever 80 from the latching position into the unlatching position. The camming member 120 is biased toward the advanced position, so as to bias the links 60, 62, to toward the normal position via the transverse shaft 52, and so as to bias the lever 80 to the latching position via the links 60, 62. The camming member 120, which extends through a narrow slot 134 in a portion 136 of the frame 76 has a longitudinal slot 140 that is closed at its forward and rearward ends and that defines a relatively short tab 142 at its rearward end and a relatively long tab 144 at its forward end. A coiled spring 150, which is disposed within the longitudinal slot 140, is piloted over the tab 142 at the rearward end of the spring 150 and bears against the frame portion 136 at the forward end of the spring 150 so as to bias the camming member 120. As the camming member 120 is advanced sufficiently, the tab 144 enters the spring 150 from the rearward end of the spring. When the lever 80 is pivoted manually from the latching position into the unlatching position, the links 60, 62, are pivoted from the normal position into the displaced position, so as to move the camming member 120 longitudinally from the advanced position into the retracted position, whereby the camming ends 104, 110, of the latches 100, 106, co-act with the horizontal portions of the camming slots 122, 124, as exemplified by the camming end 104 where shown in full lines in Figure 6. Thus, the latches 100, 106, are pivoted from the latching position into the unlatching position. When the lever 80 is released, the coiled spring 150 tends to move the camming member 120 longitudinally from the retracted position into the advanced position, whereby the camming ends 104, 110, of the latches 100, 106, co-act with the inclined portions of the camming slots 122, 124, as exemplified by the camming end 104 where shown in dashed lines in Figure 6. Thus, the links 60, 62, are pivoted from the displaced position into the normal position, so as to pivot the lever 80 from the normal position into the displaced position, and so as to pivot the latches 100, 106, from the latching position into the unlatching position. When the latches 100, 106, are pivoted into the latching position, the hooked end 102 of the forward latch 100 extends into the forward recess 70 and the hooked end 108 of the rearward latch 106 extends into the rearward recess 72, whereby the latches 100, 106, are disposed to retain the overlapped ends of a steel strap 12 between the latches 100, 106, and the base 68, and between the hooked ends 102, 108, and the frame 76. When the latches 100, 106, are pivoted into the unlatching position, the latches 100, 106, are displaced angularly from the latching position, and the hooked ends 102, 108, are removed from the recesses 70, 72, whereby the overlapped ends of the steel strap 12 can be either admitted into or removed from the strapping tool 10.

Claims: A strapping tool (10) for applying a steel strap (12) in a tensioned loop around a package and to join the strap (12) via a series of interlocking joints (16) comprising interlockable shoulders punched into overlapped ends of the strap (12), the strapping tool (10) comprising a fixed structure, which includes a base (68) extending longitudinally and a frame (78) upstanding from the base, and a mechanism (100, 106) for admitting the over-lapped ends of the strap (12) into the tool (10), for retaining the overlapped ends, and for releasing the overlapped ends from the tool (10), the mechanism including a latch (100, 106) having a hooked end (102, 108), the latch being mounted pivotably so as to be selectively pivotable between a closed position wherein the latch retains the overlapped ends and an open position wherein the latch (100, 106) is angularly displaced from the closed position to admit the overlapped ends into the tool (10) and to release the overlapped ends from the tool, the latch (100, 106) being biased into the closed position, the mechanism further including a lever (80) for moving the latch (100, 106) from the closed position into the open position, characterised in that the latch (100,106) is mounted pivotably to the base (68), in that the mechanism further comprises an elongate camming member (120) mounted movably to the frame (78) so as to be longitudinally movable between an advanced position corresponding to the closed position of the latch (100, 106) and a retracted position corresponding to the open position of the latch (100, 106), the camming member (120) having a cam slot (122, 124) co-acting with a camming end (104, 110) of the latch (100, 106) so as to pivot the latch (100, 106) from the closed position into the open position upon longitudinal movement of the camming member (120) from the advanced position into the retracted position and so as to pivot the latch (100, 106) from the open position into the closed position upon longitudinal movement of the camming member (120) from the retracted position into the advanced position, in that in the closed position the latch retains the overlapped ends between the latch (100, 106) and the base (68) and between the hooked end (102, 108) of the latch (100, 106) and the frame (68), and in that the lever (80) is linked to the camming member in such manner that pivoting of the lever (80) from the latching position into the unlatching position results in longitudinal movement of the camming member (120) from the advanced position into the retracted position, the camming member (120) being biased into the advanced position so as to bias the lever (80) into the latching position. A strapping tool according to claim 1, further comprising a handle (40) mounted pivotally to the frame (78) so as to be pivotable over a range of pivotal movement, between a forward limit of the range and a reverse limit of the range, the handle (40) being positioned near the lever (80), when the handle (40) is positioned at the reverse limit of its range, so as to permit a user to pivot the lever (80) from the latching position into the unlatching position by grasping the handle (40) and the lever (80) using only one hand and by squeezing the lever (80) toward the handle (40). A strapping tool according to claims 1 or 2, wherein the axis about which the lever (80) is pivotable is a transverse axis, and wherein the mechanism further comprises a transverse member (52) spaced from the transverse axis and arranged to move about the transverse axis as the lever (80) is pivoted about the transverse axis, the camming member (120) having another cam surface (126) co-acting with the transverse member (52) in such manner that the transverse member (52) moves the camming member (120) from the advanced position into the retracted position upon pivoting of the lever (80) from the latching position into the unlatching position. A strapping tool according to any one of the preceding claims, in which the mechanism includes a pair of latches (100, 106). A strapping tool according to any one of the preceding claims, in which the base (68) includes one or more recesses (70, 72) and in which the latch or latches (100, 106) extend into the recess or recesses (70, 72) in the closed position.

Inventors: CHUDY ANDRZEJ M, CHUDY, ANDRZEJ M.
Applicants: SIGNODE CORP, SIGNODE CORPORATION
Application year: 1994
Main classification: B65B13
IPC codes: B65B13